It won't work with a bike pump, I needed to use an air compressor on my first one as I had the same problems with the bike pump.

Just get a battery powered BBQ igniter. You can interchange it between cannons and it lasts forever.

Make an oxy acetylene mini with automatic reloading, laser sight, rifled barrel, and specially molded lead bullets.

I actually have and old pellet gun barrel, some pipe nipples, and acess to oxygen, I'll get back to you on that.

I would stick with the bushing, bell reducers (I think that's what you mean), aren't pressure rated.

If you want to see what you're getting into, keep a small plastic bottle filled with water over two electrolitic electrodes (with the opening under the surface of the water so it keeps the water in), then leave it like that with current running for a day or until the hydrogen and oxygen fill the bot...

Ive been experimenting with gunpowder lately and with firecracker-like structures only get a pop and one end plug missing. the only way to get a bang with smokeless powder like what you have (it burns slower) is to use a thick walled flat-pack explosive (a.k.a. squibs). Make them out of several laye...

It's permenant, just pay the 300 once.

Use acetylene. Or better yet, just make an electrolysis machine and hold it over the electrodes to catch hydrogen.

Edit: Hey, 300th post!

I am a green belt, and I would feel o.k. trying to disarm someone with a knife, but not a gun. I would rather carry a gun if I was in a dangerous area but I would want to be quick with it. Joanna has a point in that a good martial arts training is the best self defense, and if you know what you are ...

Why not use welding CO2 and a welding regulator. Cheaper, and will last a while.

On the general idea of arrogant fat people, reluctant though many may be to stay on the idea, the other day I saw some fat (300+#) stupid mother yelling at her kid (5 yrs) because he didn't want to go to karate and threatening to take him to the orphanage. I think fat has an effect on brain function.

I already have a jaet bike in design

Tap on fitting room doors and say in a high pitched voice, "house keeping".

Yesterday I found some tubing from an old car antenna, looks about 3mm wide.
I plan to make a lead ball mini like this one that runs off hydrogen, hope that ends well.

Go hybrid, even louder.